Mobile communication systems were developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services beyond the early voice-oriented services. However, the limited resource and user requirements for higher speed services in the current mobile communication system spur the evolution to more advanced mobile communication systems.
As one of the next-generation mobile communication systems to meet such requirements, standardization for a Long Term Evolution Advanced (LTE-A) system is underway in the 3rd Generation Partnership Project (3GPP). LTE-A is one of the high speed packet-based communication technologies supporting data rate higher than that of the current mobile communication technology under the objective to complete the standardization in late 2010.
With the evolvement of the 3GPP standard, many discussions are being conducted for optimizing the radio network in addition to the effort for increasing data rate. In mobile communication systems, small cells characterized by small service areas are frequently used to increase system throughput and remove coverage holes. However, the small cell deployment causes considerable problems in view of supporting mobility such as handover failure. Nevertheless, researches about system parameter application or operation mechanism suitable for small size service areas are very scarce.